Always feel tired? Losing weight could help beat daytime sleepiness

Reason #767 why losing weight is good for you and your life – new Australian research shows that overweight and obese people who drop some kilos will feel less sleepy throughout the day.

Many obese and overweight people complain about daytime sleepiness. Winda Liviya Ng, Baker Heart and Diabetes Institute researcher, told Coach it not only feels awful but is associated with decreased productivity at work.

"Daytime sleepiness might sound like a normal phenomenon – 30 percent of the general population experience it – but it's actually been associated with increased risk of accidents, injuries and reduced performance at work and school or university," she says.

"In the UK, one in five car accidents have been attributed to daytime sleepiness."

Ng crunched data from 42 studies that looked at daytime sleepiness in overweight and obese people, and found that those who lost weight were more bright-eyed throughout the day.

"In previous studies we had some indication that obesity is associated with daytime sleepiness, but it was unclear whether obesity causes daytime sleepiness," she says.

So she looked at research into people who had lost weight and found that they tended to feel more alert throughout the day when they'd dropped weight, up until about 40kg, when the effect plateaued.

The most pronounced results were seen in people who lost weight via surgery.

"Losing weight to a certain degree will help you improve daytime sleepiness," Ng says.

Daytime sleepiness in those with obesity has long been thought to be a result of obstructive sleep apnea, a condition where the upper airway collapses while you're sleeping to cut off the air supply and wake you up throughout the night.

But Ng says that daytime sleepiness is just as prevalent in obese people with and without sleep apnea, and people who received treatment for sleep apnea still tend to complain of daytime sleepiness.

"There may be poor mental health or short sleep duration or other mediators at play that we haven't really explored yet," Ng says.

Ng says that sleepiness and being overweight can be a vicious cycle – with daytime sleepiness making us crave more high-energy foods and less likely to exercise, which enhances our likelihood of further weight gain.

At any rate, Ng says that improving wakefulness is just one of myriad benefits to losing weight.

"The message would be that in people who are overweight or obese, sleepiness is a problem and that losing weight will help you improve the level of daytime sleepiness," she says.